The gallbladder is an organ that sits below the liver. It stores bile, which your body uses to digest fats in the small intestine.

Acute cholecystitis occurs when bile becomes trapped in the gallbladder. This often happens because a gallstone blocks the cystic duct. This is the tube that bile travels into and out of the gallbladder. When a stone blocks this duct, bile builds up, causing irritation and pressure in the gallbladder. This can lead to swelling and infection.

Other causes include:

Serious illnesses such as HIV or diabetes

Tumors of the gallbladder (rare)

Some people are more at risk for gallstones. Risk factors include:

Being female

Pregnancy

Hormone therapy

Older age

Being Native American or Hispanic

Obesity

Losing or gaining weight rapidly

Diabetes

Sometimes the bile duct becomes blocked temporarily. When this occurs repeatedly, it can lead to chronic cholecystitis. This is swelling and irritation that continues over time. Eventually, the gallbladder becomes thick and hard. It also does not store and release bile as well.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).